ATLANTA (AP) - You're on Twitter because everyone is on Twitter - chattering endlessly about life, love and snack preferences, 140 characters at a time. But are you on Twitter as efficiently as you could be?

If you're using only your profile page at Twitter.com, the answer is no. You'll want to download some free applications to manage your Twitter presence more efficiently, perhaps by categorising your followers into subgroups, embedding photos and video or conducting smarter Twitter searches.

I put some of the best Twitter-fuelled apps to the test. Some sputtered, but others are a tweeter's dream.

The best Twitter app I tested, hands down, was TweetDeck.

It arranges into columns your feed of tweets - the messages you and your friends post on Twitter. By default, your friends' tweets are displayed in the left column, with "replies" and "direct messages" (tweets directed in response to just one person) on the right. This is better than the normal method of scrolling through 200 tweets in one stream just to see what your buddy told you he ate for lunch an hour ago. His reply to you about something will be easier to find in the dedicated "replies" column.

TweetDeck's best feature is the ability to create groups of the people you're following on Twitter. You can organise them however you like - "business contacts", "bowling buddies", etc. - and then their tweets are displayed in their own columns.

TweetDeck makes things even more convenient by offering buttons that connect to other Twitter-enhancing apps, such as TwitPic, which embeds photos into your tweets; 12 Seconds, which adds video clips to tweets; and TinyURL, for shortening web addresses that you put in tweets.

Another topflight app is Twhirl. It takes up less desktop space than TweetDeck. That's because instead of side-by-side columns for replies and direct messages, it shows you those lists in different windows, which are accessible by clicking on tabs for them. Twhirl also can color-code your interactions: Replies are displayed in green while direct messages show up in yellow. If you've got the app minimised from view, a small pop-up appears on the bottom of your desktop when a new tweet arrives.

Twhirl is a fine service for those who don't need all the bells and whistles of TweetDeck.

If you really want to travel light with your desktop Twitter activity, try TwitterFox, a cool add-on for the Firefox web browser. It's one of the best ways to Twitter while multi-tasking.

TwitterFox appears as a small blue "t" in the bottom right-hand corner of the Firefox browser. If there's a number next to that "t", you've got that many new tweets to read. It also can call up different tabs for replies and direct messages.

You can set TwitterFox to get the latest tweets at intervals of three, five, 10, 15 or 30 minutes and tell you with a simple pop-up at the bottom of your screen when they've arrived. TwitterFox supports multiple Twitter accounts, so you can easily toggle between your professional and extracurricular Twitter profiles.

Another nice Firefox add-on is Twitbin. It's similar to TwitterFox, but occupies a little more real estate on the browser when it opens up as a full-length vertical sidebar.

I tested each of these Twitter apps on a Windows PC (though some are Mac compatible). For smart phones, you might try TinyTwitter and PockeTwit.

TinyTwitter is the more basic of the two. It enables quick replies, direct messages, photo embedding and retweets (a simple forwarding of someone else's brilliant tweet). PockeTwit displays larger Twitter avatars, boasts a more readable color scheme and has more intuitive menu navigation. You can even plot the physical locations of your friends on a Google map.

There's been a lot of chatter about Twitter, whether it's worthwhile, and whether it will last. I think Twitter - or a minimalist feed of user content just like it - will be with us for a while.

At its core, it's a smart chat room that gives you the ability to listen to only those voices of your choosing.

And if you deploy one of these streamlined apps, Twitter could soon be one of the most enjoyable and productive things you'll do online.